Work on nucleic acid structures has continued to evolve with a variety of collaborations and directions. Among these include DNA structural variations from straight B-DNA. Extensions have been made to the system that detects structural features in DNA and the use of a 2-dimensional version of the system for comparing multiple sequences. Further studies have ensued related to curved B-DNA in attempting to relate predicted curved sequences to their experimental gel mobility (with Jernigan, Sarai and Nussinov). Energetic calculations are progressing using the Cray which will eventually allow more accurate rules to evolve then the current models suggest for curved DNA. The DNA structure analysis program has also been enhanced to include rules for DNA melting. Using this and mutation data for procaryotic promoters research was done on how DNA local energy characteristics are related to promoter activity. The one-dimensional structural analysis program mentioned above has also been partially translated to C to run on the SUN's and/or VAXES. Also, this program now includes the ability to generate 3-D coordinates for B-DNA based upon the Calladine/Dickerson rules. Work is also progressing on a new similarity algorithm that will both pictorally and quantitatively indicate when RNA secondary structures are similar with also the possibility of developing consensus structures. Work is accelerating on the development of a nucleic acid expert system which would be directed to both intelligent queries by research and non-ad hoc structuring of relationships that exist between the various software/hardware complexes available at the Frederick Cancer Research Facility.